Thrift store PS4. What do I do to get rid of the last owners account?

Bought a used PS4 original from a thrift store. It’s in fantastic condition, just real dusty.
Just had to pop off the outside covers and blow the dust out.
Boots/runs fine, but the last owners account is on it.
What do I do to wipe/remove the previous owners account and log in with my account.
(my PS3 account should work on this, right?)

Ended up creating a new user with my account, deleting the old owner account, and doing a factory reset.